The proposed activities will continue to concentrate on the application of basic information concerning the inflammatory process to the study of disease particularly arthritis and related conditions. The specific aims include: (1) detection of immune complexes in patients, determination of their mechanism of interaction with cell with and without complement participation, and analysis of the clinical relevance of such complexes; (2) determination of the role of immunogenetic factors in patients, especially those with inherited immunoglobulin and complement deficiencies, with analysis of and B & T lymphocyte antigens, HLA ( & related markers) and other sixth chromosomal markers; (3) further analysis of the acquired abnormalities of the alternative complement pathway in paired synovial fluids and serum and how this system interacts with other humoral and cellular mediators of inflammation; (4) determination of the role of the plasma and urinary kinin-generating and fibrinolytic systems in synovial fluids, plasma and urine of patients with rheumatic diseases, vasculitis and related disorders; (5) analysis of the presence of mass cell derived mediators within the synovial fluid of patients with arthritis; (6) evaluation of the presence and mode of interaction of factors exerting chemotactic, chemokinetic, and inhibitory effects on neutrophils within the synovial fluid; (7) further characterization of the chemical mediators and related cellular events in cutaneous diseases with acquired immunologic abnormalities (immunodermatology); (8) determination of the role of humoral and cellular immunity to collagen in patients with various forms of arthritis; (9) further characterization of mediators either from lymphocytes or affecting lymphocytes; and (10) performance of studies on the effect of radiation in ameliorating rheumatoid synovitis.